This invention relates to an apparatus and method for optical inspection of the leads of semiconductor chip devices. Semiconductor chip devices come in a number of standard sizes and have protruding leads or connector pins which must be inspected during the manufacturing process to assure that the leads are aligned and have the proper end orientation. The requirement of lead inspection is to assure that the semiconductor chip devices have leads which are aligned and oriented to enable automatic insertion of the semiconductor chip device into a circuit board.
Existing lead inspection devices have an illumination system which is arranged above the device inspection station, or on the sides thereof, and an imaging system arranged either below the inspection station, or vice-versa. This arrangement is not easily suitable for use with a system that uses an automated device to pick-up and place semiconductor devices to be inspected at the inspection station of the apparatus. In the prior devices the optical system may interfere with the operation of an automated semiconductor device placement apparatus.
It is an object of the present invention to provide an improved inspection apparatus and method in which substantially all of the optical components, the illumination system and the imaging system, are positioned on only one side of the inspection station. Therefore, three-dimensional inspection of leads can be made with clearance at the top of the inspection station, so that optical inspection can take place using an automated device-handling mechanism.
In accordance with the invention, there is provided apparatus for optically inspecting connector pins of a semiconductor device. A light source is provided for providing illumination along a first optical path, which includes an optical beam splitter. A camera is arranged to receive light from the optical beam splitter along a second optical path, generally transverse to the first optical path. An inspection station is arranged to receive a semiconductor device. A surface on one side of connector pins of a semiconductor device received at the inspection station is illuminated by light from the light source. The illuminated surface provides backlight illumination of the pins. A backlit image of the pins is deflected by a light deflecting device, and reflected by the beamsplitter onto the second optical path toward the camera.
In a preferred embodiment, the inspection station comprises a horizontal platform for receiving the semiconductor device. In one arrangement for inspecting a semiconductor device having two rows of connector pins, there are provided two of the light deflector devices and two illuminated surfaces In an arrangement for inspecting a semiconductor device having four rows of connector pins, there are provided four of the first light deflecting devices and four of the illuminated surfaces.
According to the invention, the light source and the camera can be interchanged in relation to the beamsplitter.
According to the invention, a method is provided for inspecting connector pins of a semiconductor device by providing back illumination of the connector pins along a first optical path which is reflected by a beamsplitter, directing light passing the connector pins onto a second optical path towards the beamsplitter, and detecting light passing through the beamsplitter to form an image of the connector pins.
In accordance with the invention, there is also provided a method for inspecting connector pins of a semiconductor device wherein back illumination of the device connector pins is provided along a first optical which passes through the beamsplitter, wherein light passing the connection pins is directed along a second optical path toward the beamsplitter and light reflected by the beamsplitter is detected to form an image of the connecting pins.
In a preferred arrangement illumination light from the beamsplitter also directly illuminates the semiconductor pins and is reflected from the pins toward the beamsplitter to form a further image of the pins.
For a better understanding of the present invention, together with other and further objects, reference is made to the following description, taken in conjunction with the accompanying drawings, and its scope will be pointed out in the appended claims.